1. Field of the Invention
The present invention relates to a method for frequency domain equalization (FDE) of a cyclic continuous phase modulated (CPM) signal received via a channel.
2. Description of the Related Technology
There is an explosive growth in the demand for wireless connectivity. Short ranges wireless links will soon be expected to deliver bit rates of over 2 Gbit/s. Worldwide, recent regulation assigned an at least 3 GHz-wide frequency band at 60 GHz to this kind of applications. Chips for mobile consumer devices need to be power efficient; hence a suitable modulation technique for 60 GHz transceivers should allow an efficient operation of the power amplifier (PA). Moreover, these chips need to be cheap so the modulation technique should have a high level of immunity to front end nonidealities.
Continuous phase modulated (CPM) signals posses these properties. In contrast to other coherent digital phase modulation techniques where the carrier phase abruptly resets to zero at the start of every symbol (e.g. M-ary phase-shift keying (M-PSK)), with CPM the carrier phase is modulated in a continuous manner. Furthermore, they have a perfectly constant envelope which makes them much more favorable than orthogonal frequency-division multiplexing (OFDM), as cheap, power efficient nonlinear PA's can be used instead or expensive, inefficient linear ones. They are also more robust against other front end imperfections such as phase noise and analog-to-digital converter clipping and quantization. Moreover, they combine attractive spectral properties with excellent power efficiency. The primary drawback is the high implementation complexity required for an optimal receiver.